When regrinding tool components, such as a tool die or tool stamp, the length of the tool component decreases relative to the end face of the tool component by a thickness of the material that is ground away during regrinding (i.e., the regrinding length). During the lifetime of the tool component, the length of the component decreases gradually as the number of regrinding operations increases.
The information relating to the current regrinding length or the regrinding state of a tool component (e.g., a punching stamp for a punching processing operation), is typically used for optimizing the travel of the tool component during use. For example, the current punching stamp length is used both for calculating the position of the lower component (e.g., the tool die) in order to ensure that the workpiece is fully punched through, and for calculating the position at which the punching stamp is completely withdrawn from the workpiece. The regrinding length can also be used to determine if a required amount of punching travel can be performed using a selected combination of an upper tool component, such as a punching stamp and a lower tool component, such as a tool die. For example, the regrinding length can be used to determine whether or not a tool stamp is long enough to perform a required amount of punching travel while taking into account the workpiece thickness.
With tool dies, it is also useful to accurately know the regrinding length in order to provide a height compensation corresponding to the regrinding operation. Height compensation can be achieved by placing compensation discs having combined thicknesses that correspond to the regrinding length below the die so that an upper edge of the die is in alignment with the operating plane of the workpiece, regardless of the regrinding state.
It is also advantageous to be able to differentiate tool components that are new or that have not been reground from those components that have undergone at least one regrinding operation. The term tool component, as used herein, is intended to refer to various different tooling components, such as punching stamps, stamp inserts, multi-use stamps or dies or die inserts, shaping stamps, shaping dies, punching needles, and other similar tools.
The current regrinding state of a tool or tool component is typically determined by measuring the tool or tool component. This typically requires an additional operational step that requires the use of a suitable measuring device (e.g., a caliper gauge).
JP 2002 205245 A discloses a device for measuring the regrinding length of a punching stamp. To measure the regrinding length, a punching stamp is placed on a reference surface in order to bring the center of the stamp into alignment with the center of a measuring device and to position the stamp on a compensation plate. The regrinding length of the punching stamp is then measured using the measuring device.